ORAU Team

Dose Reconstruction Project for NIOSH

Application of Internal Doses Based on Claimant-Favorable 

Assumptions for Processing as Best Estimates

Document Number:

ORAUT-OTIB-0033

Effective Date: 04/20/2005

Revision No.: 00

Controlled Copy No.: _______

Page 1 of 9

Subject Expert: Elizabeth M. Brackett

Document Owner:

Approval: Signature on File Date: 04/15/2005

Edward F. Maher, Task 5 Manager

Concurrence: Signature on File Date: 04/18/2005

Richard E. Toohey, Project Director

Approval: Signature on File Date: 04/20/2005

James W. Neton, Associate Director for Science

Supersedes:

None
Effective Date: 04/20/2005 Revision No. 00 Document No. ORAUT-OTIB-0033 Page 2 of 9

RECORD OF ISSUE/REVISIONS

ISSUE 

AUTHORIZATION 

DATE

EFFECTIVE 

DATE

REV. 

NO. DESCRIPTION

Draft 04/05/2005 00-A New technical basis document to provide instructions 

on the application of overestimated internal doses for 

processing as best estimates. Initiated by Elizabeth M. 

Brackett.

Draft 04/12/2005 00-B Incorporates internal review comments. Training 

required. Initiated by Elizabeth M. Brackett.

04/20/2005 04/20/2005 00 First approved issue. Initiated by Elizabeth M. 

Brackett.
Effective Date: 04/20/2005 Revision No. 00 Document No. ORAUT-OTIB-0033 Page 3 of 9

1.0

The purpose of this document is to provide a graded approach to the application of overestimated 

internal doses in Oak Ridge Associated Universities (ORAU) Team Technical Information Bulletin 

(OTIB) ORAUT-OTIB-0018, Internal Dose Overestimates for Facilities With Air Sampling Programs, 

for processing cases in the absence of complete information. ORAUT-OTIB-0018 was written to be 

applied as an overestimate for workers with no significant intakes of particulate radioactive material. 

Because it was intended to be used only as an overestimate, it did not consider additional factors that 

could limit the upper bound for certain types of workers. 

PURPOSE

These factors include:

• The period during which the energy employee worked,

• The processes conducted at the site at which the energy employee worked,

• The job category and work location of the energy employee, and

• The results of bioassay measurements for the energy employee.

These factors are addressed here to enable application of the values in ORAUT-OTIB-0018 in a 

graded manner as the best available estimate in the absence of specific site or individual information, 

when appropriate. 

2.0

The final rule that describes the methods for dose reconstruction (42 CFR Part 82) allows the 

assumption of exposure conditions that maximize the internal dose to the organ where the cancer 

originated in cases where information in the energy employee’s personal exposure records and the 

general site information gathered for the site are insufficient to determine specific internal radiation 

exposure conditions for the case. Use of a large dose estimate to complete the dose reconstruction is 

permissible. Information obtained through additional research would not result in a higher internal 

dose to the organ where the cancer originated, and would likely lower the dose. 

BACKGROUND

This document applies to all workers covered under ORAUT-OTIB-0018; it does not extend the 

applicable periods specified in the OTIB. 

ORAUT-OTIB-0018 does not apply to intakes of tritium. Because tritium bioassay analysis is easy 

and quick, it is assumed that an individual with a significant potential for intakes was monitored. An 

assessment of these results must be included in addition to the doses applied in the OTIB.

Radioiodines are not addressed in ORAUT-OTIB-0018; doses are generally significant only for thyroid 

cancers. For thyroid cancers, the OTIB may be applied if the resultant probability of causation (POC) 

is greater than 50% for the purposes of this document. For thyroid cancers with POCs less than 50%, 

radioiodines must be added separately if a significant intake potential exists.

This document does not replace or override ORAUT-OTIB-0014, and it does not supersede any 

information in a site profile if this document contradicts that information. 

3.0

Several categories are delineated for the purpose of applying a graded approach. The dose 

reconstructor must apply judgment when determining the appropriate categories for individual workers 

and take into account all information in the worker’s file, (e.g., telephone interview information and 

EXPOSURE CATEGORIES
Effective Date: 04/20/2005 Revision No. 00 Document No. ORAUT-OTIB-0033 Page 4 of 9

external doses). A worker’s assigned category may change over time if the worker changed job titles 

or work locations.

3.1 EXPOSURE POTENTIAL

Three levels of potential exposure are applied. Attachment A provides guidance and examples on 

exposure potential specific to job and location. These are provided as guidance only; job titles could 

have had different usages at different sites. 

Seldom Exposed Above Airborne Environmental Level 

Individuals in jobs that seldom to never involved work with unsealed radioactive sources and who 

worked in locations with airborne activity levels no greater than the environmental background. 

Intermittently Exposed Above Airborne Environmental Level

Individuals with jobs that could have involved work with unsealed sources on occasion but not 

routinely, or individuals who sometimes entered an area with a potential for airborne activity levels 

greater than the environmental background.

Routinely Exposed Above Airborne Environmental Level

Individuals with jobs that were likely to have routinely involved work with unsealed sources, or

3.2 PERIOD

individuals who worked in areas likely to have airborne activity levels greater than the environmental 

background.

With the implementation of U.S. Department of Energy (DOE) Order 5480.11, Radiation Protection 

For Occupational Workers, in 1989 and the subsequent codification of requirements (10 CFR 835, 

Occupational Radiation Protection) a few years later, monitoring programs became more robust and 

personnel who had a modest exposure potential were likely to have been monitored. Respiratory 

protection was generally required for radiological areas that had levels greater than 10% of the 

derived air concentration, on which ORAUT-OTIB-0018 is based. Before that time, bioassay 

monitoring is likely to have been less organized and proceduralized, with routine monitoring at some 

sites or at particular facilities within a site but with sporadic or as-needed sampling at other sites and 

locations. Records of some of the earlier monitoring may be unavailable.

3.3 BIOASSAY

Application of this approach is divided into monitored and unmonitored individuals because the use of 

individual monitoring results takes priority over estimated values when it will make a difference to the 

compensation decision. Coworker data also takes precedence over estimated values.

Note: The unmonitored category includes those who had only a baseline or a termination 

measurement, or both.

4.0

Tables 1 and 2 show the doses to be applied for several category combinations. Table 1 applies to 

unmonitored workers, and Table 2 applies to monitored workers. 

APPLICATION OF DOSE
Effective Date: 04/20/2005 Revision No. 00 Document No. ORAUT-OTIB-0033 Page 5 of 9

Table 1: Unmonitored Personnel

Category Exposure Potential Period Application of Dose

1 Seldom All ORAUT-OTIB-0014

2 Intermittent Before 1989 50% ORAUT-OTIB-0018

3 Intermittent 1989 and later 5% ORAUT-OTIB-0018

4 Routine Before 1989 1. Coworker data

2. ORAUT-OTIB-0018

5 Routine 1989 and later 1. Coworker data

2. 10% ORAUT-OTIB-0018

Unmonitored categories 2 and 3: The application of 50% of the corresponding “routine” category 

value is based on the assumption that an individual in category 2 or 3 is intermittently exposed. 

Because the occupancy factor is assumed to be uniformly distributed from 0 to 1, a mean value of 0.5 

is applied to the ORAUT-OTIB-0018 value (or to the 10% value in 1989 or later, resulting in a total of 

5% of the ORAUT-OTIB-0018 value). The geometric standard deviation remains the same.

Unmonitored categories 4 and 5

Table 2: Monitored Personnel

: Coworker data are applied if available; otherwise ORAUT-OTIB0018 (or applicable fraction) is acceptable.

Category

Exposure 

Potential Period Bioassay Application of Dose

1 All All All results < MDAa 1. Coworker data

2. Missed dose determination

3. ORAUT-OTIB-0018 

2 All All Incidents and/or 

results > MDA

1. IMBA application for all internal dose 

2. ORAUT-OTIB-0018 + assessment of 

positive results 

a. MDA = minimum detectable amount or activity; results less than those given in Table 7-1 of ORAUT-OTIB-0018 may be 

considered in the < MDA category.

Monitored category 1: Coworker data are considered to be the best estimate for this case. ORAUTOTIB-0018 may be applied as an overestimate to the systemic organs in the absence of coworker 

data but, if it yields a POC greater than 47%, a missed dose calculation must be performed if 

adequate information is available. The OTIB might not be an overestimate of non-systemic organ 

(respiratory and gastrointestinal tract) doses, so if it yields a POC less than 50%, coworker data or 

missed dose must be applied. 

Monitored category 2: If the application of ORAUT-OTIB-0018 plus the dose from assessment of the 

positive results yields a POC greater than 47%, an assessment based on the worker’s bioassay must 

be performed if adequate information is available.
Effective Date: 04/20/2005 Revision No. 00 Document No. ORAUT-OTIB-0033 Page 6 of 9

REFERENCES

DOE (U.S. Department of Energy), 1988, “Radiation Protection For Occupational Workers,” Order 

5480.11, Washington, D.C., December 21.

ORAU (Oak Ridge Associated Universities), 2004, Assignment of Environmental Internal Doses for 

Employees Not Exposed to Airborne Radionuclides in the Workplace, ORAUT-OTIB-0014, 

Oak Ridge, Tennessee.

ORAU (Oak Ridge Associated Universities), 2005, Internal Dose Overestimates for Facilities With Air 

Sampling Programs, ORAUT-OTIB-0018, Oak Ridge, Tennessee.
Effective Date: 04/20/2005 Revision No. 00 Document No. ORAUT-OTIB-0033 Page 7 of 9

ATTACHMENT A 

EXPOSURE POTENTIALS

(Page 1 of 3)

Job Categories

Likely low

Administrator

potential for work with unsealed sources

Assistant

Business systems specialist

Cafeteria worker

Checker

Clerk

Computer specialist

Dispatcher

Draftsman

Groundskeeper

Instructor

Manager

Medical technician

Office supervisor

Planner

Quality assurance specialist

Program analyst

Programmer

Radio operator

Recruiter

Scheduler

Secretary

Telephone operator

Possible some

Biologist

potential for work with unsealed sources, depending on job specifics

Boilermaker

Bricklayer

Carpenter

Construction worker

Driver

Electrician

Electronics technician

Engineer

Equipment operator

Firefighter

Foreman

Foundry worker

Heavy equipment operator

HP analyst

Instrument mechanic

Insulator

Ironworker

Janitor

Laborer

Mechanic

Painter

Patrolman

Photographer

Scientist

Security guard

Specialist

Storekeeper

Supervisor

Surveyor

Technician

Likely high

Analytical chemist

potential for work with unsealed sources

Assembly worker

Chemical operator

Fabricator

Glovebox worker

Health physics technician

Machinist

Material handler

Metallurgist

Millwright

Pipefitter

Plumber

Processor

Production worker

Radiation monitor

Radiochemist

Reactor operator

Steamfitter

Ventilation and balance 

operator

Waste handler

Welder
Effective Date: 04/20/2005 Revision No. 00 Document No. ORAUT-OTIB-0033 Page 8 of 9

ATTACHMENT A 

EXPOSURE POTENTIALS

(Page 2 of 3)

Example Work Locations

High Potential for Airborne Activity (alpha, beta/gamma, and/or uranium)

• Uranium refining – Fernald and Weldon Spring (natural, depleted, and enriched uranium 

reactor fuel and targets); Oak Ridge National Laboratory (weapons parts and highly enriched 

reactor fuel); K-25, Paducah, and Portsmouth Gaseous Diffusion Plants (production of UF6

feed) 

• Fuel and target fabrication – Highly enriched uranium: Savannah River Site 300 M Area;

Hanford 300 Area

• Chemical separations facility – Weapons plutonium: Hanford 200 East and West Areas 

(PUREX, REDOX, T and B Plants, 231-Z Plant); Savannah River Site (F Canyon complex) 

Uranium recycling: Hanford (UO3 Plant, U Plant); Savannah River Site (H Canyon complex); 

Idaho National Engineering Laboratory (Idaho Chemical Processing Plant)

• Weapons component fabrication facility – Plutonium: Rocky Flats; Hanford 234-5 Plutonium 

Finishing Plant; Los Alamos (TA-21 and TA-55)

• Weapons component fabrication facility – Plutonium recycling: Rocky Flats; Hanford 234-5 

Plutonium Finishing Plant; Los Alamos (TA-55) Highly enriched uranium; Y-12; Rocky Flats

• Isotope separation – Uranium: K-25, Paducah, and Portsmouth Gaseous Diffusion Plants

• Reactor operations – Hanford (B, D, F, H, DR, C, KW, KE, and N Reactors); Savannah River 

Site (R, P, K, L, and C Reactors) 

• Weapons testing – Test sites: Nevada Test Site; Bikini and Enewetak Atolls; Christmas and 

Johnston Islands; Amchitka Island; Tonopah Test Range; Salton Sea Test Base

• Weapons research and development: Los Alamos; Lawrence Livermore; Sandia (New Mexico 

and California)

• Uranium ore sampling – Fernald and Middlesex

• Other facilities with the potential for airborne uranium or plutonium

Low Potential for Airborne Activity (alpha, beta/gamma, and/or uranium)

• Chemical separations facility – Tritium: Savannah River Site 

• Weapons component fabrication facility – Tritium including recovery and recycling: Mound; 

Savannah River Site (Tritium Facility), Lithium-6 deuteride including recovery and recycling: 

Oak Ridge Y-12

• Weapons operations – Assembly and dismantlement: Sandia; Pantex; Burlington
Effective Date: 04/20/2005 Revision No. 00 Document No. ORAUT-OTIB-0033 Page 9 of 9

ATTACHMENT A 

EXPOSURE POTENTIALS

(Page 3 of 3)

• Weapons operations – Modifications and maintenance: Pantex; Burlington; Sandia; 

Clarksville; Medina Modification Centers

• Isotope separation – Lithium: Y-12 COLEX and ELEX Plants

• Isotope separation – Heavy water: Savannah River Site Heavy Water Plant; Dana Heavy 

Water Plant

• Fuel and target fabrication – Enriched Lithium: Y-12; Savannah River Site M Area 

• Administrative and Support Facilities or other non-radiological facility